Alan Faulkner's Forefront Security Blog

Here I am going to show you how to write your own custom Commerce Server event and utilize it in the Data Warehouse for reporting purposes.  In this case, we are going to create a fictitious MusicDownload event, which, if you have a music Commerce Server site, can record an event on every music download.  This event will keep track of the Artist, Album, and Title.  This will be a two part series where the first part focuses on the custom event and part 2 focuses on extending the Data Warehouse. 

• Let's create a new DLL C# project.  We need to Add a Reference to the Microsoft.CommerceServer.Runtime dll.  You can find this dll in the C:\Program Files\Microsoft Commerce Server 2007\Assemblies\ directory.
• So now we create the Class MusicDownloadEvent.  To have a Commerce Server event, we need to extend the BaseCommerceEvent, thus overriding the Validate Method.  Here is the entire class with comments below:

      1 using System;

      2 using System.Collections.Generic;

      3 using System.Text;

      4 using Microsoft.CommerceServer.Runtime;

      5 

      6 namespace CompanyName.Project.MusicDownloads

      7 {

      8     [CommerceEvent("MusicDownload")]

      9     public class MusicDownloadEvent : BaseCommerceEvent

     10     {

     11         #region Members

     12         string _title;

     13         string _artist;

     14         string _album;     

     15         #endregion

     16 

     17         /// <summary>

     18         /// Default Constructor

     19         /// </summary>

     20         public MusicDownloadEvent()

     21             : base()

     22         {

     23 

     24         }

     25 

     26         public MusicDownloadEvent(string title, string artist, string album)

     27         {

     28             _title = title;

     29             _artist = artist;

     30             _album = album;

     31 

     32         }

     33 

     34         [CommerceEventMember("Artist")]

     35         public string Artist

     36         {

     37             get { return _artist; }

     38             set { _artist = value; }

     39         }

     40 

     41         [CommerceEventMember("Album")]

     42         public string Album

     43         {

     44             get { return _album; }

     45             set { _album = value; }

     46         }

     47 

     48         [CommerceEventMember("Title")]

     49         public string Title

     50         {

     51             get { return _title; }

     52             set { _title = value; }

     53         }

     54 

     55         /// <summary>

     56         /// Validates that this is a valid Event

     57         /// </summary>

     58         /// <returns></returns>

     59         public override bool Validate()

     60         {

     61             if (string.IsNullOrEmpty(_title) ||

     62                 string.IsNullOrEmpty(_artist) ||

     63                 string.IsNullOrEmpty(_album))

     64             {

     65                 return false;

     66             }

     67             return base.Validate();

     68         }

     69     }

     70 }

• You notice that we had to apply attributes to the class indicating that this is a Commerce Event with the name "MusicDownload".  This is required. 

      8  [CommerceEvent("MusicDownload")]

      9     public class MusicDownloadEvent : BaseCommerceEvent

• You also notice that each property that we want to include in the event must have the attribute CommerceEventMember, with the event name as a parameter, as illustrated below:

     34  [CommerceEventMember("Artist")]

     35         public string Artist

     36         {

     37             get { return _artist; }

     38             set { _artist = value; }

     39         }

• Once you compile and sign this dll, you need to add the DLL as a reference in the site's Visual Studio project. 

• Next, you need to add the entry for the event in your web.config file.  It's important to note that the assembly name must be fully qualified.  Here is what our MusicDownloadEvent looks like in the web.config file:

 <add className="CompanyName.Project.MusicDownloads.MusicDownloadEvent, CompanyName.Project.MusicDownloads, Version=1.0.0.0, Culture=neutral" id="MusicDownload" loggingEnabled="true"/>

• Now, let's create a very simplistic Aspx page that uses this event, here it is below:

      1 using System;

      2 using System.Data;

      3 using System.Configuration;

      4 using System.Collections;

      5 using System.Web;

      6 using System.Web.Security;

      7 using System.Web.UI;

      8 using System.Web.UI.WebControls;

      9 using System.Web.UI.WebControls.WebParts;

     10 using System.Web.UI.HtmlControls;

     11 using CompanyName.Project.MusicDownloads;

     12 using Microsoft.CommerceServer.Runtime;

     13 

     14 

     15 public partial class MusicDownload : System.Web.UI.Page

     16 {

     17     protected void Page_Load(object sender, EventArgs e)

     18     {

     19         MusicDownloadEvent evt = new MusicDownloadEvent("Back in black", "AC/DC", "Unknown");

     20         CommerceContext.LogCommerceEvent(evt);

     21 

     22     }

     23 }

• Next Step is to Extend the Data Warehouse to include this event.  This will be covered in Part 2, where I hope to have some utilities that will make it easy for you to extend!